We’re not saying you can’t wear any of these items. But if you do, you’re going to die alone.
You’ll notice it says shouldn’t, not can’t, in the title. If you have the youthful looks and/or physique to pull off any of these items, by all means wear them (at your peril). Some people have a strong sense of style and know what works for them*. That being said, I think when you cross the 30 threshold you should take a good hard look at yourself in the mirror and think: ‘I’m a man’.